s of bacteria, spherical, rod-like and spiral bacteria

background bacteria bacterium biology cells close closeup coli colorful disease epidemic escherichia fever germs helicobacter illness illustration infection isolated life medical medicine metagenomic micro microbes microbiology microorganisms microscope microscopic mycobacterium pylori pyogenic rodlike rods rodshaped sample science scientific shapes spherical spiral spirilla staphylococci staphylococcus white